Apparatus and method for wireless communication

ABSTRACT

An apparatus for wireless communication includes a classification unit and an allocation unit. The classification unit classifies communication devices in a cell where the apparatus is located, the communication devices are classified into a plurality of communication device groups including a first communication device group and a second communication device group. The allocation unit allocates pilot frequency sequences in a first pilot frequency group to the first communication device group, and allocates pilot frequency sequences in a second pilot frequency group to the second communication device group. When the number of the pilot frequency sequences is insufficient, a multiplexing configuration is executed, such as communication devices in the second communication device group multiplex at least one pilot frequency sequence in the second pilot frequency group.

FIELD OF THE INVENTION

The embodiments of the present disclosure generally relate to thetechnical field of wireless communications, and in particular to anapparatus and a method for wireless communications. More specifically,the embodiments of the present disclosure relate to a pilot allocationtechnology in a large-scale Multiple-Input Multiple-Output (MIMO)communication system.

BACKGROUND OF THE INVENTION

Large scale MIMO systems have been widely focused by both the academiaand the industry in recent years. Theoretical studies have demonstratedthat, both spectral efficiency and energy efficiency of the large-scaleMIMO system can be significantly improved by using simple lineralgorithms, such as a zero-forcing algorithm, a minimum mean squarealgorithm and the like. Therefore, the large-scale MIMO system is likelyto be adopted as a key technology in next generation communicationstandards.

However the system performance of the large-scale MIMO system is limitedby pilot pollution problem in a scenario of, for example, multi-celltime-division multiplexing. Specifically, since the length of the pilotis limited by a coherence length of a channel the number of orthogonalpilots is limited, and the pilots may be inevitably shared amongdifferent cells. In this case, pilot signals transmitted by userequipments in different cells using the same pilot sequence may bereceived by a base station in a neighboring cell, which, however, cannoteffectively distinguish the pilot signals from each other, therebyresulting in interferences to uplink channel estimation at the basestation. When performing uplink data detection using the interferedchannel estimation, the base station may receive data from userequipments in other cells, besides data transmitted by user equipmentsin the cell where the base station is located thereby resulting ininter-cell interferences in the uplink. When the base station generatesa pre-coding matrix and transmits downlink data using the interferedchannel estimation, besides the user equipments in the cell where thebase station is located, user equipments in other cells may also receivethe data, thereby resulting in inter-cell interferences in the downlink.

Theoretical studies have demonstrated that, although both spectralefficiency and energy efficiency of the large-scale MIMO system can besignificantly improved, and the influences of noises and channelestimation error on the system performance are reduced as the number ofantennas of the base station is increased, the inter-cell interferencescaused by the pilot pollution cannot be eliminated and become one of thefactors limiting the performance of the large-scale MIMO system.

In addition, conventional methods for alleviating the pilot pollutionare often difficult to be adapted to current technical conditions.Therefore, in actual applications, the pilot pollution is still one ofthe most serious problems confronted by the large-scale MIMO system.

SUMMARY OF THE INVENTION

In the following, an overview of the present invention is given simplyto provide basic understanding to some aspects of the present invention.It should be understood that this overview is not an exhaustive overviewof the present invention. It is not intended to determine a criticalpart or an important part of the present invention, nor to limit thescope of the present invention. An object of the overview is only togive some concepts in a simplified manner which serves as a preface of amore detailed description described later.

According to an aspect of the present disclosure, there is provided anapparatus for wireless communications, including: a classification unit,configured to classify communication devices in a cell where theapparatus is located into a plurality of communication device groups,wherein the plurality of communication device groups include a firstcommunication device group and a second communication device group; andan allocation unit, configured to allocate pilot sequences in a firstpilot group to the first communication device group, and allocate pilotsequences in a second pilot group to the second communication devicegroup, wherein at least one of the following reuse configurations isperformed in the case that the pilot sequences are insufficient: atleast part of the communication devices in the second communicationdevice group reuse at least one of the pilot sequences in the secondpilot group, and at least one communication device in the secondcommunication device group of the cell and at least one communicationdevice in a second communication device group of a neighboring cellwhich is subjected to the same classification reuse at least one of thepilot sequences in the second pilot group.

According to another aspect of the present disclosure, there is provideda method for wireless communications, including: classifyingcommunication devices in a cell into a plurality of communication devicegroups, wherein the plurality of communication device groups include afirst communication device group and a second communication devicegroup; and allocating pilot sequences in a first pilot group to the lastcommunication device group, and allocating pilot sequences in a secondpilot group to the second communication device group, and at least oneof the following reuse configurations is performed in the case the thepilot sequences are insufficient: at least part of the communicationdevices in the second communication device group reuse at least one ofthe pilot sequences in the second pilot group, and at least onecommunication device in the second communication device group of thecell and at least one communication device in a second communicationdevice group of a neighboring cell which is subjected to the sameclassification reuse at least one of the pilot sequences in the secondpilot group.

According to yet another aspect of the present disclosure, there isfurther provided an apparatus for wireless communications, including oneor more processors configured to: classify communication devices in acell into a plurality of communication device groups, wherein theplurality of communication device groups include a first communicationdevice group and a second communication device group, and allocate pilotsequences in a first pilot group to the first communication devicegroup, and allocate pilot sequences in a second pilot group to thesecond communication device group, wherein at least one of the followingreuse configurations is performed in the case that the pilot sequencesare insufficient: at least part of the communication devices in thesecond communication device group reuse at least one of the pilotsequences in the second pilot group, and at least one communicationdevice in the second communication device group of the cell and at leastone communication device in a second communication device group of aneighboring cell which is subjected to the same classification reuse atleast one of the pilot sequences in the second pilot group.

According to other aspects of the present disclosure, there are alsoprovided computer program codes and computer program products forimplementing the above mentioned methods for wireless communications anda computer readable storage medium in which computer program codes forimplementing the above method for wireless communications are recorded.

The apparatus and the method according to the present disclosure canobtain at least one of the following effects by causing a part of thecommunication devices to reuse pilot sequences: alleviating the pilotpollution, increasing the utilization efficiency of the pilot sequences,enhancing the accuracy of uplink channel estimation performed by thebase station, improving the downlink pre-coding performed by the basestation based on the uplink channel estimation, thereby improving thecommunication quality of the communication devices, and enhancing theoverall performance of the system.

These and other advantages of the present disclosure will be moreapparent by illustrating in detail a preferred embodiment of the presentinvention in conjunction with accompanying drawings below.

BRIEF DESCRIPTION OF THE DRAWINGS

To further set forth the above and other advantages and features of thepresent invention, detailed description will be made in the followingtaken in conjunction with accompanying drawings in which identical orlike reference signs designate identical or like components. Theaccompanying drawings, together with the detailed description below, areincorporated into and form a part of the specification, it should benoted that the accompanying drawings only illustrate, by way of example,typical embodiments of the present invention and should not be construedas a limitation to the scope of the invention. In the accompanyingdrawings:

FIG. 1 illustrates a block diagram of an apparatus for wirelesscommunications according to an embodiment of the present disclosure;

FIG. 2 illustrates a schematic example of the communication devices inthe second communication device group of the cell reusing pilotsequences;

FIG. 3 illustrates a graph showing the comparison between systemperformance acquired by using a conventional method and that acquired byusing the time-division reusing method according to the presentdisclosure;

FIG. 4 illustrates a schematic diagram of a multi-cell multi-user mobilecellular system which is closer, to the actual situation;

FIG. 5 illustrates a simulation result based oil the mobile cellularsystem shown, in FIG. 4;

FIG. 6 illustrates an example of a non-uniform time-division reusingscheme;

FIG. 7 illustrates an example of a scheme of edge pilot sequences beingreused among neighboring cells;

FIG. 8 illustrates another example of the scheme of edge pilot sequencesbeing reused among neighboring cells:

FIG. 9 illustrates another example of the scheme of edge pilot sequencesbeing reused among neighboring cells;

FIG. 10 illustrates an example of adjusting the reusing scheme throughsignaling interaction;

FIG. 11 illustrates an example of a scheme of center pilot sequencesbeing reused within the cell;

FIG. 12 illustrates a block diagram of an apparatus for wirelesscommunications according to another embodiment of the presentdisclosure;

FIG. 13 illustrates a block diagram of an apparatus for wirelesscommunications according to another embodiment of the presentdisclosure;

FIG. 14 illustrates a block diagram of an apparatus at a communicationdevice side according to an embodiment of the present disclosure;

FIG. 15 is a flow chart illustrating a method for wirelesscommunications, according to an embodiment of the present disclosure;and

FIG. 16 is an exemplary block diagram illustrating the structure of ageneral purpose personal computer capable of realizing the method and/orapparatus and/or system according to the embodiments of the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment of the present invention will be describedhereinafter in conjunction with the accompanying drawings. For thepurpose of conciseness and clarity, not all features of an embodimentare described in this specification. However, if should be understoodthat multiple decisions specific to the embodiment have to be made in aprocess of developing any such embodiment to realize a particular objectof a developer, for example, conforming to those constraints related toa system and a business and these constraints may change as theembodiments differ. Furthermore, it should also be understood thatalthough the development work may be very complicated andtime-consuming, for those skilled in the art benefiting from the presentdisclosure, such development work is only a routine task.

Herein, it should also be noted that in order to avoid obscuring thepresent invention due to unnecessary details, only a desire structureand or processing steps closely related to the solution according to thepresent invention are illustrated in the accompanying drawing, and otherdetails having little relationship to the present invention are omitted.

<First Embodiment>

FIG. 1 illustrates a block diagram of a structure of an apparatus 100for wireless communications according to an embodiment of the presentdisclosure. The apparatus 100 includes: a classification unit 101,configured to classify communication devices in a cell where theapparatus 100 is located into a plurality of communication devicegroups, wherein the plurality of communication device groups include afirst communication device group and a second communication devicegroup; and an allocation unit 102, configured to allocate pilotsequences in a first pilot group to the first communication devicegroup, and allocate pilot sequences in a second pilot group to thesecond communication device group, wherein at least one of the followingreuse configurations is performed in the case that the pilot sequencesare insufficient: at least part of the communication devices in thesecond communication device group reuse at least one of the pilotsequences in the second pilot group, and at least one communicationdevice in the second communication device group of the cell and at leastone communication device in a second communication device group of aneighboring cell which is subjected to the same classification reuse atleast one of the pilot sequences in the second pilot group.

For example, in the mobile cellular communication, the apparatus 100 maybe a base station equipment. In addition, although an example of theapparatus 100 being a base station equipment is shown herein, thepresent disclosure is not limited thereto. For example, the apparatus100 may also be a base-band cloud device under a C-RAN(Cloud-RAN/Centralized-RAN) structure (in which there may be no such aconcept as a cell), such as any BBU in BBU pools connected in high-speedconnections with each other under the C-RAN architecture. Thecommunication device described herein may be a user equipment such as amobile terminal, an intelligent chicle, or an intelligent wearabledevice, which has cellular communication capabilities, or may be aninfrastructure such as a small cell base station being capable ofperforming wireless communications with a macro base station.

The first pilot group and the second pilot group may be configured inadvance for each cell, for example, by an OAM. Alternatively, the firstpilot group and the second pilot group may be grouped and informed torespective cells by a control apparatus which manages multiple cells. Inthis case, the control apparatus respectively determines the first pilotgroup and the second pilot group for cells within the management scopeof the control apparatus. For example, the control apparatus may beimplemented as any type of server, such as a tower server, a rack serveror a blade server, which is used for providing controlling services tomultiple cells/base stations. The control apparatus may be a controlmodule installed on the server (such as an integrated circuit moduleincluding a single wafer, and a card or a blade inserted into a slot ofthe blade server). The advantage of performing the grouping by thecontrol apparatus which manages multiple cells lies in that, forexample, pilot sequences contained in the first pilot group and thesecond pilot group of respective cells can be dynamically adjusted basedon an overall consideration on the number of devices contained in thefirst communication device group and that in the second communicationdevice group of respective cells, and thus the overall communicationquality and the overall pilot utilization efficiency of the multiplecells can be optimized.

Further, although not shown in FIG. 1, the apparatus 100 may furtherinclude a grouping unit configured to group the pilot sequences forwireless communications into the first pilot group and the second pilotgroup, to be respectively allocated to the first communication devicegroup and the second communication device group. In this case, thenumbers of pilot sequences in the first pilot group and the second pilotgroup may be changed according to, for example, variation in adistribution of the numbers of devices in the first communication devicegroup and the second communication device group. That is, a moreflexible dynamic grouping can be implemented, so as to further increasethe utilization efficiency of the pilot sequences.

As described above, due to the limitation of a channel coherence length,the number of available pilot sequences is limited. Therefore, varioustechniques need, to be adopted to increase the utilization efficiency ofpilot sequences and to alleviate the pilot pollution between neighboringcells. In the apparatus 100, the pilot sequences are grouped into thefirst pilot group and the second pilot group, which are respectivelyallocated to different communication device groups, and the pilotsequences in the second pilot group are reused intra-cell or inter-cellby the allocation unit 102.

Preferably, the pilot sequences in the first pilot group are orthogonalto the pilot sequences in the second pilot group. However, as analternative example, the pilot sequences in the first pilot group maypartially overlap with the pilot sequences in the second pilot group,thereby increasing flexibility of pilot sequence allocation in order tocope with a scenario where the pilot sequences are insufficient, forexample, due to a sudden increase in the number of the communicationdevices in the cell.

Preferably, the above reusing is time-division reusing, i.e., differentcommunication devices occupy different time resources, in order to avoidpilot pollution. Alternatively, the reusing may also be code-divisionreusing. In the following, a specific description is made by taking thetime-division reusing as an example. However, it is to be noted that,the description is not restrictive, and can be expanded to other reusingmanners.

In an example, the classification unit 101 is configured to classify acommunication device on an edge of a cell into the second communicationdevice group. In other words, the second communication device group isan edge communication device group. Correspondingly, the firstcommunication device group is a center communication device group. Thecommunication devices on the cell edge are susceptible to interferencesfrom communication devices in the neighboring cell, while thecommunication devices in the cell center have better channel conditionsand are less susceptible to interferences from the neighboring cell.

Therefore, the following configuration can be made: at least part of thepilot sequences in the first pilot group corresponding to the cell arethe same as at least part of the pilot sequences in a first pilot groupcorresponding to the neighboring cell, and the pilot sequences in thesecond pilot group corresponding to the cell are different from thepilot sequences in the second pilot group corresponding to theneighboring cell. In this way, pilot sequences are allocated bydistinguishing different channel conditions of the cell edge and thecell center, and the limited pilot sequences can be fully utilized whileavoiding the pilot pollution problem. In the following, the pilotsequences in the first pilot group are also referred as center pilots,and the pilot sequences in the second pilot group are also referred asedge pilots.

In this case, the apparatus 100 may determine, based on, for example, acell ID (CID) of the cell, the pilot sequences contained in the secondpilot group corresponding to the cell. Specifically, for example, thecontrol apparatus mentioned above may divide all of the pilot sequencesto be allocated to the edge communication devices of cells into multiplepilot sub-groups, and allocate one of the pilot sub-groups to each cellaccording to the cell ID of the cell, for example, by a mod(CID, N)operation. For example, in the case that there are at least 3 pilotsub-groups, a serial number of a pilot sub-group of a cell may bedetermined according to a value of CID of the cell mod 3, therebyensuring that the same pilot sub-group would not be allocated toneighboring cells. The allocation may also be performed based oncalculating using such as a coloring algorithm. Further, the pilotsub-groups may be determined in advance, for example, may be configuredby an OAM, and the apparatus 100 can directly determine the pilotsequences allocated to the edge communication device of the cell wherethe apparatus 100 is located according to CID.

Since neighboring cells use different pilot sub-groups, the number ofpilot sequences in the pilot sub-group of each cell may be quitelimited. According to an example of the present disclosure, in the casethat the number of the pilot sequences in the second pilot groupcorresponding to the cell is less than the number of the communicationdevices in the second communication device group, the allocation unit102 configures at least part of the communication devices in the secondcommunication device group to occupy different time resources so as totransmit at least one of the reused pilot sequences in the second pilotgroup. By enabling several communication devices to reuse one pilotsequence in a time division manner, the pilot pollution can be avoided,and the utilization efficiency of pilot sequences can be increased.

The different time resources correspond to, for example, different timeslots, and for one time slot, the communication devices configured tooccupy other time slots to transmit pilot sequences do not transmit anydata or pilot sequence. Of course, for one time slot, the communicationdevices configured to occupy other time slots may transmit only data. Inaddition, the time resources may also refer to subframes, frames, or thelike. That is, different subframes or frames are allocated to differentcommunication devices. Although the following description is given bytaking time slots as an example of the time resources, the presentdisclosure is not limited thereto, and the time resources may also betime units with other definitions.

FIG. 2 illustrates a schematic example of the communication devices inthe second communication device group of the cell reusing pilotsequences, where a multi-cell multi-user mobile cellular networkscenario is shown on the left side. It is assumed that a radius of thecell is 500 meters, a propagation path loss index is 2, and the shadowfading effect is not taken into consideration. It is also assumed thatpositions of users are fixed, and influences from noises are neglected.As shown in FIG. 2, assuming that each of cells 1 to 3 has 5 users, thenumber of available orthogonal pilot sequences is 5, where a first pilotgroup {ϕ₁,ϕ₂} is allocated to center users (user 1 and user 2) of threecells, and second pilot groups {ϕ₃}, {ϕ₄}, and {ϕ₅} are respectivelyallocated to edge users (user 3, user 4 and user 5) of three cells.

The center users can directly use the pilot sequences in the first pilotgroup, with center users in neighboring cells using the same pilotsequences. For edge users, the allocation unit 102 enables three edgeusers in the cell to share one pilot sequencer in a time-divisionreusing manner. The specific allocation conditions of the pilotsequences are shown on the right side of FIG. 2. As can be seen, in thisexample, the center users 1 and 2 respectively occupy all of the timeslots of ϕ₁ and ϕ₂, while in respective cells, the edge users 3 occupytime slots 1 of {ϕ₃}, {ϕ₄}, and {ϕ₅} respectively, the edge users 4occupy time slots 2 of {ϕ₃}, {ϕ₄}, and {ϕ₅} respectively, and the edgeusers 5 occupy time slots 3 of {ϕ₃}, {ϕ₄}, and {ϕ₅} respectively. Inthis case, the pilot sequence in the second pilot group of each cell isoccupied by only one user at the same time instant, thereby avoidingintra-cell and inter-cell pilot pollutions. Further, since thetime-division reusing scheme is adopted, multiple users, of which thenumber is greater than the number of pilot sequences, are enabled to usesame pilot sequences and a good supplementation for the above technicalscheme where neighboring cells use different second pilot groups isfurther provided.

FIG. 3 illustrates a trend of the variation of an average uplinkcapacity of users with the number of base station antennas M in thisexample. The average uplink capacity of center users in an i-th cell canbe calculated with the following equation (1):C _(i) =E{log₂(1+SINR_(ik))}, k=1, . . . , K ₁   (1)where K_(i) represents the number of center users, SINR_(ik) representsa signal-to-interference-and-noise ratio of a k-th center user in thei-th cell. Similarly, the average uplink capacity of edge users can becalculated with the following equation (2):

$\begin{matrix}{{C_{i} = {\frac{1}{K_{2}}E\{ {\log_{2}( {1 + {SINR}_{ik}} )} \}}},{k = {K_{1} + 1}},\ldots\mspace{14mu},K} & (2)\end{matrix}$where K is the number of all users, the factor 1/K₂ represents anefficiency factor due to the time-division reusing method. Solid linesin FIG. 3 illustrates average uplink capacities respectively acquired byusing a conventional method and the time-division reusing methodaccording to the present disclosure (based on a TDMA scheme) for thecenter users, while dotted lines illustrates a comparison betweenperformances respectively acquired using the two methods for edge users,where triangles represent the conventional method, and circles representthe method according to the present disclosure. As can be seen, a subtleincrement in performance can be provided for the center users by usingthe time-division reusing method according to the present disclosure,since in the conventional method, K users are performing communicationssimultaneously in a cell, while in the method according to the presentdisclosure, the number of users performing communications in a cellwithin any time slot is less than K, and thus interferences within thecell are reduced. However, in the conventional method, the capacity ofthe edge users, which is about 0.5 bps/Hz as shown in FIG. 3, is low dueto the pilot pollution, and can not increase with the number of basestation antennas. By using the method according to the presentdisclosure, the edge users share edge pilot sequences in a time-divisionreusing manner, and thus the pilot pollution is completely eliminated.In the case that the number of base station antennas is small, theperformance acquired using the method according to the presentdisclosure is close to the performance acquired using the conventionalmethod. However, when the number of the base station antennas increases,the average uplink capacity of edge users increases significantly sincethere is no pilot pollution. For example, in the case that the number ofbase station antennas M=128, the average uplink capacity of edge usersin this example acquired using the method according to the presentdisclosure is about three times of that acquired using the conventionalmethod.

FIG. 4 illustrates a schematic diagram of another multi-cell multi-usermobile cellular system which is more complex and closer to the actualsituation. A simulation is performed on this system in order to acquirea performance comparison between the conventional method and the methodaccording the present disclosure. In this system, there are a total of 7cells, i.e., L=7, the number of base station antennas M is from 3 to128, the number of users K in the cell (i.e., the total number of pilotsequences) is 14, the number of center pilot sequences K_(i) is 7, aradius of the cell R is 500 meters, a cell edge signal-to-noise ratioSNR is 20 dB, a user average emission energy is 0 dB, a base stationaverage emission energy is 10 dB, a path loss exponent α is 2, and alogarithmically distributed shadow fading σ is 8 dB.

A large-scale fading factor β_(ijk) of a channel between a k-th user ina j-th cell to a base station in an i-th cell is calculated using thefollowing equation (3).

$\begin{matrix}{\beta_{ijk} = \frac{z_{ijk}}{( {r_{ijk}/R} )^{\alpha}}} & (3)\end{matrix}$where z_(ijk) represents a shadow fading effect coefficient, whichfollows a logarithmic distribution with a standard deviation σ=8 dB(10log₁₀(z_(ijk)) follows a Gaussian distribution with a mean 0 and astandard deviation σ), r_(ijk) represents a distance between the k-thuser in the j-th cell to the base station in the i-th cell. During eachsimulation, positions of users are randomly generated. Squares andtriangles in FIG. 4 respectively represent center users and edge users(the related classification of the center users and the edge users willbe described specifically later).

FIG. 3 illustrates average uplink channel capacities of users in thiscomplex scenario. As can be seen, for the center users, the performancesrespectively acquired using the conventional method and thetime-division, reusing method according to the present disclosure aresimilar. However, for the edge users, since there are a relatively greatnumber of neighboring cells in the actual system (up to 6), the pilotpollution problem is serious, and thus the edge users can hardlycommunicate with the base station. Even in the case that the number ofbase station antennas M reaches a maximum number of 128, the channelcapacity is still only about 0.1 bps/Hz. However, by using the methodaccording to the present disclosure, the uplink channel capacity of theedge users can increase with the number of base station antennas M, andreach about 1 bps/Hz in the case that the number of base stationantennas M is 128. The communication quality of the edge users isgreatly enhanced as compared with the conventional method.

It is to be noted that, in the above method, time slots are of a uniformlength in time. However, the time slots may be set to have differentlengths. In addition the allocation unit 102 of each cell may decide themanner in which the edge users reuse pilot resources by itself, forexample, the allocation unit 102 may decide a certain edge user wouldoccupy which one of ones of time slots by itself. FIG. 6 illustrates anexample of a non-uniform time-division reusing scheme. In cell 1, 3 of 6time slots are allocated to edge user (UE) 5, 2 time slots are allocatedto edge user 3, and only 1 time slot is allocated to edge user 1. Incell 2, the allocation is performed in a fixed cycling order. In cellthe allocation manner is flexible. Of course, the time slots in thisexample may be replaced by sub-frames or frames, or the like.

In the above description, the pilot sequences in the second pilot groupcorresponding to the cell are different from the pilot sequences in thesecond pilot group corresponding to the neighboring cell. However, thefollowing configuration may be performed: at least part of the pilotsequences in the second pilot group corresponding to the cell are thesame as at least part of the pilot sequences in the second pilot groupcorresponding to the neighboring cell, and the allocation unit 102 isconfigured to cause at least part of the communication devices in thesecond communication device group of the cell and the communicationdevices in the second communication device group of the neighboring cellto reuse the part of pilot sequences.

In other words, since neighboring cells use different pilot sub-groups,the number of pilot sequences in the pilot sub-group of each cell may bequite limited. According to an example of the present disclosure, a partof pilot sequences may be reused between cells. The reusing here may beone of time-division reusing and code-division reusing the time-divisionreusing is still taken as an example. The allocation unit 102 may beconfigured to determine, for each of the part of pilot sequences, a timeslot within a frame to be occupied by the communication device in thesecond communication device group of the cell, so as to coordinate withthe neighboring cell. That is, as long as it is ensured that in eachtime slot, the pilot sequences used by the communication devices in thesecond device group of the cell are orthogonal to the pilot sequencesused by the communication devices in the second device group of theneighboring cell.

The simple system shown in FIG. 2 is still taken as an example. Thefirst communication device group includes user 1 and user 2, the secondcommunication device group includes users 3, 4 and 5, the first pilotgroup includes pilot sequences ϕ₁ and ϕ₂ (which are center pilotsequences), and the second pilot group includes pilot sequences ϕ₃, ϕ₄and ϕ₅ (which are edge pilot sequences). FIGS. 7 to 9 illustrateexamples of the schemes of edge pilot sequences being reused amongneighboring cells,

As shown in FIG. 7, in time slot T1, edge pilot sequences ϕ₃, ϕ₄ and ϕ₅are used by three edge users in cell 1. As an example, edge users incell 2 and cell 3 are in the sleep state, that is, they do not transmitdata and pilot sequences. Similarly, in time slot T2, edge pilotsequences ϕ₃, ϕ₄ and ϕ₅ are used by three edge users in cell 2, and edgeusers in cell 1 and cell 3 are in the sleep state. In time slot T3, edgepilot sequences ϕ₃, ϕ₄ and ϕ₅ are used by three edge users in cell 3 andedge users in cell 1 and cell 2 are in the sleep state. Of course, foreach time slot, edge users of cells which do not occupy this time slotmay also transmit only data in this time slot.

As an example, the allocation unit 102 is configured to determine,according to a cell ID of the cell, a position of the time slot to beoccupied by the communication device. For example, it is possible toperform modulo operation of the cell ID on a predetermined value such asthe maximum number of neighboring cells and take the acquired remainderas the time slot to be occupied by the communication device.

FIG. 8 illustrates another reusing scheme, which is different from thescheme shown in FIG. 7 in that, cell 1 has 4 edge users, i.e., cell 1further includes edge user 6. The scheme shown in FIG. 8 illustrates howuser 5 and user 6 in cell 1 further reuse the edge pilot sequence in atime-division manner. As can be seen in this scheme, user 5 and user 6alternately occupy time slot T1 of edge pilot sequence ϕ₃ allocated tocell 1. It should be understood that the above is only an example, andother reusing manner may be adopted.

FIG. 9 illustrates yet another reusing scheme. In schemes shown in FIG.7 and FIG. 8, time slots are of a uniform length and consist of a basictime slot. The basic time slot includes four portions, i.e., an uplinkpilot transmission portion, an uplink data transmission portion, a basestation processing portion and a downlink data transmission portion.However, each time slot may consist of multiple basic time slots. Forexample, as shown in FIG. 9, T1 consists of 2 basic time slots. In cell1, the 2 basic time slots are respectively used by user 5 and user 6,while in cell 2, the 2 basic time slots are both used by user 3. Thisreusing scheme may be considered as combining both intra-cell reusingand inter-cell reusing. In addition, time slots may be of non-uniformlengths. For example, T1 consists of 3 basic time slots, T2 consists of2 basic time slots, and T3 consists of 1 basic lime slot, or the like.

It should be understood that, the setting of the reusing scheme is notlimited to the examples shown in FIGS. 7 to 9, but may be changedaccording to actual requirements and user distribution conditions.

As another example, the allocation unit 102 may dynamically determine aposition of the time slot to be occupied by the communication deicethrough signaling interaction between cells. In this way, time slots ofthe pilot sequences in the second pilot group may be allocated in a moreflexible manner. For example, as long as the condition that one edgepilot sequence is occupied by only one edge user in one time slot ismet, that will do. For example, the allocation unit 102 performs theinteraction via X2 signaling between cells.

For example, in the case that distributions of edge users in respectivecells are not uniform, this situation may be reported through signalinginteraction between cells, and the reusing scheme may be adjustedaccording. FIG. 10(a) illustrates an example of a simple applicationscenario with three cells, where each of cell 1, cell 2 and cell 3includes two center users 1 and 2, and cell 1 includes edge users 3, 4and 5. However, each of cell 2 and cell 3 includes only edge user 3,which is different from the example shown in FIG. 2. Therefore, as shownin FIG. 10(b), if the reusing scheme shown in FIG. 2 is still used,i.e., in time slot 2 and time slot pilot sequence ϕ₃ and pilot sequenceϕ₄ would be idle. If the scheme shown in FIG. 10(c) is used, the user incell 3 may be configured to occupy the time slots of these pilotsequences, thereby increasing the utilization efficiency of pilotsequences.

In the above, situations where the pilot sequences in the second pilotgroup are reused are described. The communication devices in the firstcommunication device group may also be enabled to reuse the pilotsequences in the first pilot group. For example, in the scenario shownin FIG. 2, FIG. 4 or FIG. 10, if the number of the edge users is small,but the edge users have high requirement on communications, while thenumber of center users is great, the center users may be enabled toreuse the center pilot sequences. FIG. 11 illustrates an example ofcenter users reusing center pilot sequences in a time-division manner.As shown in FIG. 11(a), there are a total of 3 cells, each cell has 4users, of which three are center users, and one is an edge user, andthere are a total of 4 orthogonal pilot sequences. As shown in FIG.10(b), one of the pilot sequences is a center pilot sequence, and theother three pilot sequences are edge sequences. For edge user 4, sinceeach cell includes only one edge user, it is not necessary to performreusing, instead, the edge users can directly use the edge pilotsequences. For center users, since each cell includes three centerusers, these center users need to reuse the center pilot sequences in atime-division manner.

In summary, the apparatus 100 according to the present disclosure iscapable of increasing the utilization efficiency of pilot sequenceswhile enhancing the overall performance of the communication system, byenabling communication devices to reuse pilot sequences intra-celland/or inter-cell.

<Second Embodiment>

FIG. 12 illustrates a block diagram of an apparatus 200 for wirelesscommunications according to another embodiment of the presentdisclosure. Besides the units shown in FIG. 1, the apparatus 200 furtherincludes a notification unit 201 configured to notify a correspondingcommunication device of information on the allocated pilot sequence andtime resource.

The information may be contained in, for example, at least one of PDCCHsignaling and RRC signaling.

For example, the transmission period and the sub frame offset of thepilot sequence may be configured using the RRC signaling. Communicationdevices involved in the reusing have different subframe offsets. Asdescribed above, the allocation unit 102 may select, according to thecell ID, an edge pilot sequence which takes a cyclic shift as the index.The apparatus 200 may further include a signaling generation unit (notshown in FIG. 12), which is configured to generate the RRC signalingwhich includes the transmission period and the subframe offset of thepilot sequence and information indicating the cyclic shift of the pilotsequence.

The pilot sequence here may be uplink pilot sequence allocation, such asallocation of SRS (Sounding Reference Signal) in the LTE-A standard.

Further, in an example of the present disclosure, when a target UE needsto reuse a certain pilot sequence with another UE, the target UE doesnot transmit the pilot sequence when the time slot is occupied by theanother UE. Therefore, a scheduler contained in the apparatus 200schedules based on the allocation configuration of the pilot sequence,physical resources for the target UE, and thus does not allocateresources to the target UE for data transmission thereby avoiding wasteof resources. For example, for a resource block (RB) in a correspondingtime slot, the signaling generation unit generates correspondingdownlink control information for resource scheduling for only UEs otherthan the target UE, and maps the information to PDCCH signaling fortransmission.

In the case that there exist interactions between cells as described inthe first embodiment, the notification unit 201 may further beconfigured to transmit information such as user distribution conditionsof the cell where the apparatus 200 is located to the neighboring cell,so as to implement interactions between cells.

<Third Embodiment>

As described in the first embodiment, the classification unit 101classifies communication devices on the cell edge to the secondcommunication device group. In this embodiment, the classification unitmay be configured to perform the classification according to channelconditions of the communication device. For example, a communicationdevice with good channel conditions is classified into the firstcommunication device group, and a communication device with poor channelconditions is classified into the second communication device group.

As shown in FIG. 13, besides the units in the apparatus 100, theapparatus 300 for wireless communications according to this embodimentfurther includes a reception unit 301 configured to receive channelquality measurement information and or a radio resource managementmeasurement report from the communication device. The channel qualitymeasurement information and/or the radio resource management measurementreport are used by the classification unit 101 to determine the channelconditions of the communication device. Although not shown in FIG. 13,the apparatus 300 may also include the notification unit 201 shown inFIG. 12.

The channel quality measurement information such as CQI is used forindicating the communication quality between the communication deviceand the base station currently serving the communication device. Theradio resource management measurement report indicates a signalreception intensity of the communication device for the neighboringcell. For example, transmission of the measurement report may betriggered only in the case that a certain condition is met. For example,in LTE-A, the user equipment reports to the base station only themeasurement result of the neighboring cell for which the signalreception intensity is great enough or meets a predetermined condition.

The reception unit 301 receives at least one of the above two types ofinformation. The classification unit 101 determines the channelconditions of the communication device according to the receivedinformation, and classifies the communication device into the firstcommunication device group or the second communication device group. Forexample, in the case that the channel conditions are good, thecommunication device is determined as a center user and classified intothe first communication device group, otherwise, the communicationdevice is classified into the second communication device group.

In an example, in the case that the signal reception intensity for theneighboring cell is above a predetermined threshold, the classificationunit 101 classifies the communication device into the secondcommunication device group. This is because a high signal receptionintensity for the neighboring cell indicates that the communicationdevice is subjected to a severe interference from the neighboring cell,and thus the communication device has poor channel conditions and shouldbe determined as the edge user. In the case that there exist reports formultiple neighboring cells, if a maximum signal reception intensityamong them reaches the predetermined threshold, the communication devicecan be determined as the edge user.

In addition, the communication device may also be determined as the edgeuser in the case that the signal reception intensity for the neighboringcell is higher than the signal reception intensity for the cell wherethe communication device is located. Of course, the determination mayalso be made according to only the signal reception intensity for thecell where the communication device is located. For example, thecommunication device may be determined as the edge user in the case thatthe signal reception intensity for the cell where the communicationdevice is located is lower than a predetermined threshold.

Further, the judgment of the edge user may also be performed bydynamically configuring corresponding conditions as required. Forexample, when there are a relatively great number of idle edge pilotsequences, the edge user judgment condition may be set to be lessstrict, and more users may be determined as edge users, while when theedge pilot sequences are insufficient, the edge user judgment conditionmay be set to be stricter such that more users use the center pilotsequences.

In another example, the classification unit 101 is configured to rankthe communication devices according to channel qualities, and classify apredetermined number of communication devices with optimum channelqualities into the first communication device group and classify therest of communication devices into the second communication devicegroup. In this case, the classification is performed according to, forexample, only the signal reception intensity for the cell where thecommunication device is located. The predetermined number may be thenumber of pilot sequences in the first pilot group, i.e., the centerusers use pilot sequences which are orthogonal to each other, and theedge users may reuse the edge pilot sequences.

In addition, the classification may be performed according to the signalreception intensities for the neighboring cell. For example, theclassification unit 101 ranks the communication devices according tosignal reception intensities for the neighboring cell, and classifies apredetermined number of communication devices with greatest signalreception intensities into the second communication device group andclassifies the rest of communication devices into the firstcommunication device group. The predetermined number may be the numberof pilot sequences in the second pilot group, i.e., the edge users usepilot sequences which are orthogonal to each other, and the center usersmay reuse the center pilot sequences,

Of course, the determination whether the communication device is thecenter user or the edge user may be performed by the communicationdevice itself, and the determination result is notified by thecommunication device to the apparatus 100.

Besides performing the classification according to channel conditions,the classification unit 101 may also classify the communication devicesaccording to other standards.

For example the classification unit 101 may be configured to perform theclassification according to an access order of the communication devicesand preferentially classify the communication devices which are firstaccessed into the first communication device group. In this case, forexample, the pilot sequences in the first pilot group are exclusivepilot sequences, and the pilot sequences in the second pilot group areshaded pilot sequences. There are multiple users in the cell, and thetime instants at which the users access to the system are different.According to a first-come first-serve principle, when a certain useraccesses to the system, an idle exclusive pilot sequence, if there isany, is allocated to this user, otherwise a certain time slot of atime-division reused pilot sequence is allocated to this user.

As another example, the allocation unit 103 may preferentially performreuse configuration on the communication device with a lower prioritylevel. For example, when a user accesses to the system, the usersimultaneously informs the system of a QoS requirement of the user, ahigher QoS requirement indicates a higher priority level, while a lowerQoS requirement indicates a lower priority level. The allocation unit102 allocates a pilot sequence to the communication device according tothe QoS requirement thereof. For example, the allocation unit 102preferentially performs the reuse configuration for the communicationdevice which performs large volume data transmission with a low latencyrequirement, and allocates one or more time slots of the time-divisionsensed pilot sequences to the communication device.

In addition, apparatuses 100 to 300 may dynamically perform theoperation. Specifically, the classification unit 101 is configured todynamically perform the classification based on a state of thecommunication device, and the allocation unit 102 correspondinglydynamically performs allocation and reuse configuration.

For example, when the channel conditions of the communication devicechange, the classification unit 101 may perform reclassification, andthe allocation unit 102 allocates the pilot sequence according to theresult of the reclassification, and performs reuse configuration whennecessary. Alternately, when the priority level of the communicationdevice changes, the classification unit 101 and the allocation unit 102may also dynamically perform classification and allocation accordingly.That is, the classification unit 101 performs the classification basedon trigger or request.

As an example, when a certain center user moves, its communicationquality may be degraded. At this time, the center user transmits arequest to the base station. On reception of the request, the basestation checks whether there is an idle time slot in the edge pilotsequences of the cell. If there is an idle time slot, the base stationswitches the center user to the edge user and allocates the idle timeslot to the edge user, in order to ensure the communication quality ofthe edge user. If there is no idle time slot, the base station notifiesthe center user to maintain its current state.

Similarly, when a certain edge user gets a better channel quality andwants to acquire a higher data transmission rate, the edge usertransmits a request to the base station. On reception of the request,the base station checks whether there is an idle center pilot sequencein the cell where the base station is located. If there is an idlecenter pilot sequence, the base station switches the edge user to thecenter user. If there is no idle center plot sequence, the base stationnotifies the edge user to maintain its current state.

In addition, the classification unit 101 may also periodically classifythe communication devices. For example, the classification unit 101performs reclassification when a predetermined period timer expires. Itshould be understood that, the classification unit 101 may performoperation by combining both the periodic classification and triggered(requested) classification.

<Fourth Embodiment>

In the following, a structure of an apparatus 400 at the communicationdevice side is described with reference to FIG. 14. The apparatus 400includes: a transmission unit 401, configured to transmit a request forthe pilot sequence to the base station, and a reception unit 402,configured to receive information on the allocated pilot sequence andtime slot from the base station.

In an example, the transmission unit 401 is further configured totransmit the channel quality measurement information and/or the radioresource management measurement report to the base station. After that,the base station side classifies the present communication deviceaccording to the received information, and allocates the pilot sequence.In the case that reusing is required, the base station also allocatesthe time slot to be occupied.

In addition, as shown by the dotted line block in FIG. 14, the apparatus400 may further include a determination unit 403 configured to determinewhether the communication device where the apparatus is located is anedge communication device of a center communication device, and thetransmission unit 401 is configured to transmit a judgmentidentification to the base station. The judgment identificationindicates whether the communication device is the edge communicationdevice or the center communication device.

As an example, the determination unit 403 may perform the determinationaccording to the signal reception intensity for the neighboring cell andthe signal reception intensity for the cell where the communicationdevice is located. In the case that there is a neighboring cell forwhich the signal reception intensity is greater than the signalreception intensity for the cell where the communication device islocated, the communication device is determined as the edgecommunication device.

Alternatively, the reception unit 402 may also receive a threshold forthe above determination from the base station. In the case that thesignal reception intensity for the neighboring cell is higher than thethreshold, the determination unit 403 determines the communicationdevice as the edge communication device. Alternatively, in the case thatthe signal reception intensity for the cell where the communicationdevice is located is lower than the threshold, the determination unit403 determines the communication device as the edge communicationdevice.

After the determination unit 403 determines the category of thecommunication device, the transmission unit 402 transmits acorresponding judgment identification to the base station, to enable thebase station to allocate the pilot sequence and the time slot for thecommunication device. The base station side may perform theclassification, allocation and reuse configuration using the apparatus100 according to the first to third embodiments. However, the presentdisclosure is not limited thereto.

<Fifth Embodiment>

In the process of describing the apparatus for wireless communicationsin the embodiments described above, obviously, some processing andmethods are also disclosed. Hereinafter, an overview of the methods isgiven without repeating some details disclosed above. However, it shouldbe noted that, although the methods are disclosed in a process ofdescribing the apparatus for wireless communications, the methods do notcertainly employ or are not certainly executed by the aforementionedcomponents. For example, the embodiments of the apparatus for wirelesscommunications may be partially or completely implemented with hardwareand or firmware, the method for wireless communications described belowmay be executed by a computer-executable program completely, althoughthe hardware and or firmware of the apparatus for wirelesscommunications can also be used in the methods.

FIG. 15 illustrates a flowchart of a method for wireless communicationsaccording to an embodiment of the present disclosure. The methodincludes the following steps: classifying communication devices in acell into a plurality of communication device groups, wherein theplurality of communication device groups comprise a first communicationdevice group and a second communication device group (S11); andallocating pilot sequences in a first pilot group to the firstcommunication device group, and allocating pilot sequences in a secondpilot group to the second communication device group (S12), wherein atleast one of the following reuse configurations is performed in the casethat the pilot sequences are insufficient (S13): at least part of thecommunication devices in the second communication device group reuse atleast one of the pilot sequences in the second pilot group, and at leastone communication device in the second communication device group of thecell and at least one communication device in a second communicationdevice group of a neighboring cell which is subjected to the sameclassification reuse at least one of the pilot sequences in the secondpilot group.

Preferably the pilot sequences in the first pilot group are orthogonalto the pilot sequences in the second pilot group.

The above reusing may be time-division reusing, and may also befrequency-division reusing or code-division reusing.

In an example in step S11, the communication device on a cell edge isclassified into the second communication device group. Theclassification may be performed according to, for example, channelconditions of the communication device. As shown by the dotted lineblock in FIG. 15, before step S11, the method may further includes stepS21, in which channel quality measurement information and/or a radioresource management measurement report are received from thecommunication device for determining the channel conditions of thecommunication device in step S11. Of course, the communication deviceitself may determine its own channel conditions and determine whetherthe communication device is the center user or the edge user accordingto the channel conditions. In this case, a judgment identificationindicating the judgment result is received from the communication devicein step S21, and the classification is performed according to thereceived judgment identification in step S11.

The radio resource management measurement report includes the signalreception intensity of the communication device for the neighboringcell. In the case that the signal reception intensity for theneighboring cell is above a predetermined threshold, the communicationdevice is classified into the second communication device group in stepS11.

In another example, in step S11, the communication devices are rankedaccording to channel qualities, and a predetermined number ofcommunication devices with, optimum channel qualities are classifiedinto the first communication device group and the rest of communicationdevices are classified into the second communication device group. Thepredetermined number may be the number of pilot sequences in the firstpilot group. Similarly, in step S11, the communication devices may alsobe ranked according to signal reception intensities for the neighboringcell, and a predetermined number of communication devices with greatestsignal reception intensifies are classified into the secondcommunication device group and the rest of communication devices areclassified into the first communication device group. The predeterminednumber may be the number of pilot sequences in the second pilot group.

In addition, in step S11, the classification may be performed accordingto an access order of the communication devices, and the communicationdevices which are first accessed are preferentially classified into thefirst communication device group. Alternatively, in step S11, reuseconfiguration may be preferentially performed on the communicationdevice with a lower priority level.

Steps S11 to S13 may be dynamically performed based on a state of thecommunication device.

In an example, at least part of the pilot sequences in the first pilotgroup corresponding to the cell are the same as at least part of thepilot sequences in a first pilot group corresponding to the neighboringcell and the pilot sequences in the second pilot group corresponding tothe cell are different from the pilot sequences in the second pilotgroup corresponding to the neighboring cell. The pilot sequencescontained in the second pilot group corresponding to the cell may bedetermined according to a cell ID of the cell. As described above, thefirst pilot and the second pilot group may be determined in advance, ormay be notified by a control terminal over the base station.Alternatively, the pilot sequences may be grouped by the base stationside itself. Specific details are described in the first embodiment andare not repeated here.

In the case that the number of the pilot sequences in the second pilotgroup corresponding to the cell is less than the number of thecommunication devices in the second communication device group, in stepS13, at least part of the communication devices in the secondcommunication device group are configured to occupy different timeresources so as to transmit at least one of the reused pilot sequencesin the second pilot group.

The different time resources correspond to different time slots. For onetime slot, the communication devices configured to occupy other timeslots do not transmit any data or pilot sequence.

In another aspect, at least part of the pilot sequences in the secondpilot group corresponding to the cell are the same as at least, part ofthe pilot sequences in the second pilot group corresponding to theneighboring cell. In step S13, at least part of the communicationdevices in the second communication device group of the cell and thecommunication devices in the second communication device group of theneighboring cell are caused to reuse the part of pilot sequences.

For each of the part of pilot sequences, in step S13, a time slot withina frame to be occupied by the communication device in the secondcommunication device group of the cell is determined, so as tocoordinate with the neighboring cell. That is, as long as it is ensuredthat at a same time instant, the pilot sequences used by thecommunication devices in the second device group of the cell areorthogonal to the pilot sequences used by the communication devices inthe second device group of a different cell, that will do,

As an example, in step S13, a position of the time slot to be occupiedby the communication device may be determined according to a cell ID ofthe cell. Is addition, in step S13, the position of the time slot to beoccupied by the communication device may be dynamically determinedthrough signaling interaction between, cells. When signaling interactionoccurs between cells, a more flexible reuse configuration may beperformed.

As shown by the dotted box in FIG. 15, the above method may furtherinclude step S31, in which information on the allocated pilot sequenceand time resource is notified to a corresponding communication device.These information mas be contained in at least one of PDCCH signalingand RRC signaling.

It is to be noted that, details of the above method are described in thefirst to fourth embodiments, and are not repeated here.

The basic principle of the present invention has been described above inconjunction with particular embodiments. However, as can be appreciatedby those ordinarily skilled in the art, all or any of the steps orcomponents of the method and device according to the invention can beimplemented in hardware, firmware, software or a combination thereof inany computing device (including a processor, a storage medium, etc.) ora network of computing devices by those ordinarily skilled in the art inlight of the disclosure of tire invention and making use of theirgeneral circuit designing knowledge or general programming skills.

It can be understood by those skilled in the art that, in the apparatusdescribed above, the classification unit, the allocation unit, thedetermination unit and the like can be implemented by one or moreprocessors, and the notification unit, the reception unit, thetransmission unit and the like can be implemented by a circuit elementsuch as an antenna, a filter, a modem and a codec.

Therefore, there is further provided an electronic device (1) accordingto the present disclosure, which includes circuitry configured to:classify communication devices in a cell into a plurality ofcommunication device groups, wherein the plurality of communicationdevice groups comprise a first communication device group and a secondcommunication device group; and allocate pilot sequences in a firstpilot group to the first communication device group, and allocate pilotsequences in a second pilot group to the second communication devicegroup, wherein at least one of the following reuse configurations isperformed in the case that the pilot sequences are insufficient: atleast part of the communication devices in the second communicationdevice group reuse at least one of the pilot sequences in the secondpilot group, and at least one communication device in the secondcommunication device group of the cell and at least one communicationdevice in a second communication device group of a neighboring cellwhich is subjected to the same classification reuse at least one of thepilot sequences in the second pilot group.

Moreover, the present invention further discloses a program product inwhich machine-readable instruction codes are stored. The aforementionedmethods according to the embodiments can be implemented when theinstruction codes are read and executed by a machine.

Accordingly, a memory medium for earning the program product in whichmachine-readable instruction codes are stored is also covered in thepresent invention. The memory medium includes but is not limited to softdisc, optical disc, magnetic optical disc, memory card, memory stick andthe like.

In the case where the present application is realized by software orfirmware, a program constituting the software is installed in a computerwith a dedicated hardware structure (e.g. the general computer 1000shown in FIG. 16) from a storage medium or network, wherein the computeris capable of implementing various functions when installed with variousprograms.

In FIG. 16, a central processing unit (CPU) 1601 executes variousprocessing according to a program stored in a read-only memory (ROM)1602 or a program loaded to a random access memory (RAM) 1603 from amemory section 1608. The data needed for the various processing of theCPU 1601 may be stored in the RAM 1603 as needed. The CPU 1601, the ROM1602 and the RAM 1603 are linked with each other via a bus 1604. Aninput/output interface 1605 is also linked to the bus 1604.

The following components are linked to the input/output interface 1605:an input section 1606 (including keyboard, mouse and the like), anoutput section 1607 (including displays such as a cathode ray tube(CRT), a liquid crystal display (LCD), a loudspeaker and the like), amemory section 1608 (including hard disc and the like), and acommunication section 1609 (including a network interface card such as aLAN card, modem and the like). The communication section 1609 performscommunication processing via a network such as the Internet. A driver1610 may also be linked to the input/output 1605. If needed, a removablemedium 1611, for example, a magnetic disc, an optical disc, a magneticoptical disc, a semiconductor memory and the like, may be installed inthe driver 1610, so that the computer program read therefrom isinstalled in the memory section 1608 as appropriate.

In the case where the foregoing series of processing is achieved bysoftware, programs forming the software are installed from a networksuch as the Internet or a memory medium such as the removable medium1611.

It should be appreciated by those skilled in the art that the memorymedium is not limited to the removable medium 1611 shown in FIG. 16,which has program stored therein and is distributed separately from theapparatus so as to provide the programs to users. The removable medium1611 may be, for example, a magnetic disc (including floppy disc(registered trademark)), a compact disc (including compact discread-only memory (CD-ROM) and digital versatile disc (DVD), a magnetooptical disc (including mini disc (MD)(registered trademark)), and asemiconductor memory. Alternatively, the memory medium may be the harddiscs included in ROM 1602 and the memory section 1608 in which programsare stored, and can be distributed to users along with the device inwhich they are incorporated.

To be further noted, in the apparatus, method and system according tothe invention, the respective components or steps can be decomposed andor recombined. These decompositions and/or recombinations shall beregarded as equivalent schemes of the invention. Moreover, the aboveseries of processing steps can naturally be performed temporally in thesequence as described above but will not be limited thereto, and some ofthe steps can be performed in parallel or independently from each other.

Finally, to be further noted, the term “include”, “comprise” or anyvariant thereof is intended to encompass nonexclusive inclusion so thata process, method, article or device including a series of elementsincludes not only those elements but also other elements which have beennot listed definitely or an element(s) inherent to the process, method,article or device. Moreover, the expression “comprising a(n) . . . ” inwhich an element is defined will not preclude presence of an additionalidentical element(s) in a process, method, article or device comprisingthe defined elements(s)” unless further defined.

Although the embodiments of the invention have been described above indetail in connection with the drawings, it shall be appreciated that theembodiments as described above ate merely illustrative but notlimitative of the invention. Those skilled in the art can make variousmodifications and variations to the above embodiments without departingfrom the spirit and scope of the invention. Therefore, the scope of theinvention defined merely by the appended claims and their equivalents.

The invention claimed is:
 1. An apparatus for wireless communications,comprising: circuitry configured to classify communication devices in acell where the apparatus is located into a plurality of communicationdevice groups, the plurality of communication device groups comprising afirst communication device group and a second communication devicegroup; and allocate pilot sequences in a first pilot group to the firstcommunication device group, and allocate pilot sequences in a secondpilot group to the second communication device group, wherein at leastone of the following reuse configurations is performed in the case thatthe pilot sequences are insufficient: at least part of the communicationdevices in the second communication device group reuse at least one ofthe pilot sequences in the second pilot group, and at least onecommunication device in the second communication device group of thecell and at least one communication device in a second communicationdevice group of a neighboring cell which is subjected to the sameclassification reuse at least one of the pilot sequences in the secondpilot group, and at least part of the pilot sequences in the first pilotgroup corresponding to the cell are the same as at least part of thepilot sequences in a first pilot group corresponding to the neighboringcell, and the pilot sequences in the second pilot group corresponding tothe cell are different from the pilot sequences in the second pilotgroup corresponding to the neighboring cell, and wherein the circuitryis further configured to classify a communication device located on anedge of the cell into the second communication device group and performthe classification according to channel conditions of the communicationdevice.
 2. The apparatus according to claim 1, wherein the pilotsequences in the first pilot group are orthogonal to the pilot sequencesin the second pilot group.
 3. The apparatus according to claim 1,wherein the reusing is time division reusing.
 4. An apparatus forwireless communications, comprising: circuitry configured to classifycommunication devices in a cell where the apparatus is located into aplurality of communication device groups, the plurality of communicationdevice groups comprising a first communication device group and a secondcommunication device group; and allocate pilot sequences in a firstpilot group to the first communication device group, and allocate pilotsequences in a second pilot group to the second communication devicegroup, wherein at least one of the following reuse configurations isperformed in the case that the pilot sequences are insufficient: atleast part of the communication devices in the second communicationdevice group reuse at least one of the pilot sequences in the secondpilot group, and at least one communication device in the secondcommunication device group of the cell and at least one communicationdevice in a second communication device group of a neighboring cellwhich is subjected to the same classification reuse at least one of thepilot sequences in the second pilot group, and at least part of thepilot sequences in the first pilot group corresponding to the cell arethe same as at least part of the pilot sequences in a first pilot groupcorresponding to the neighboring cell, and the pilot sequences in thesecond pilot group corresponding to the cell are different from thepilot sequences in the second pilot group corresponding to theneighboring cell, wherein the apparatus is configured to determine,based on a cell ID of the cell, the pilot sequences contained in thesecond pilot group corresponding to the cell.
 5. The apparatus accordingto claim 4, wherein the circuitry is further configured to configure atleast part of the communication devices in the second communicationdevice group to occupy different time resources so as to transmit atleast one of the reused pilot sequences in the second pilot group, inthe case that the number of the pilot sequences contained in the secondpilot group corresponding to the cell is smaller than the number of thecommunication devices in the second communication device group.
 6. Theapparatus according to claim 5, wherein the different time resourcescorrespond to different time slots, and for one time slot, thecommunication devices configured to occupy other time slots do nottransmit any data or pilot sequence.
 7. An apparatus for wirelesscommunications, comprising: circuitry configured to classifycommunication devices in a cell where the apparatus is located into aplurality of communication device groups, the plurality of communicationdevice groups comprising a first communication device group and a secondcommunication device group; and allocate pilot sequences in a firstpilot group to the first communication device group, and allocate pilotsequences in a second pilot group to the second communication devicegroup, wherein at least one of the following reuse configurations isperformed in the case that the pilot sequences are insufficient: atleast part of the communication devices in the second communicationdevice group reuse at least one of the pilot sequences in the secondpilot group, and at least one communication device in the secondcommunication device group of the cell and at least one communicationdevice in a second communication device group of a neighboring cellwhich is subjected to the same classification reuse at least one of thepilot sequences in the second pilot group, and at least part of thepilot sequences in the first pilot group corresponding to the cell arethe same as at least part of the pilot sequences in a first pilot groupcorresponding to the neighboring cell, and the pilot sequences in thesecond pilot group corresponding to the cell are different from thepilot sequences in the second pilot group corresponding to theneighboring cell, wherein at least part of the pilot sequences in thesecond pilot group corresponding to the cell are the same as at leastpart of the pilot sequences in the second pilot group corresponding tothe neighboring cell, and the circuitry is further configured to causeat least part of the communication devices in the second communicationdevice group of the cell and the communication devices in the secondcommunication device group of the neighboring cell to reuse the part ofpilot sequences.
 8. The apparatus according to claim 7, wherein thecircuitry is further configured to determine, for each of the part ofpilot sequences, a time slot within a frame to be occupied by thecommunication device in the second communication device group of thecell, so as to coordinate with the neighboring cell.
 9. The apparatusaccording to claim 8, wherein the circuitry is further configured todetermine, according to a cell ID of the cell, a position of the timeslot to be occupied by the communication device.
 10. The apparatusaccording to claim 8, wherein the circuitry is further configured todynamically determine a position of the time slot to be occupied by thecommunication device through signaling interaction between cells. 11.The apparatus according to claim 5, wherein the circuitry is furtherconfigured to notify a corresponding communication device of informationon the allocated pilot sequence and time resource.
 12. The apparatusaccording to claim 11, wherein the information is contained in at leastone of PDCCH signaling and RRC signaling.
 13. The apparatus according toclaim 1, wherein the circuitry is further configured to receive, fromthe communication device, channel quality measurement information and/ora radio resource management measurement report, which are used by thecircuitry to determine the channel conditions of the communicationdevice.
 14. The apparatus according to claim 1, wherein the circuitry isfurther configured to perform the classification according to an accessorder of the communication devices, and preferentially classify thecommunication devices which are first accessed into the firstcommunication device group.
 15. The apparatus according to claim 1,wherein the circuitry preferentially performs reuse configuration on thecommunication device with a lower priority level.
 16. The apparatusaccording to claim 1, wherein the circuitry is further configured todynamically perform the classification based on a state of thecommunication device, and correspondingly dynamically perform theallocation and reuse configuration.
 17. A method for wirelesscommunications, comprising: classifying communication devices in a cellinto a plurality of communication device groups, wherein the pluralityof communication device groups comprise a first communication devicegroup and a second communication device group; and allocating pilotsequences in a first pilot group to the first communication devicegroup, and allocating pilot sequences in a second pilot group to thesecond communication device group, wherein at least one of the followingreuse configurations is performed in the case that the pilot sequencesare insufficient: at least part of the communication devices in thesecond communication device group reuse at least one of the pilotsequences in the second pilot group, and at least one communicationdevice in the second communication device group of the cell and at leastone communication device in a second communication device group of aneighboring cell which is subjected to the same classification reuse atleast one of the pilot sequences in the second pilot group, and whereinthe circuitry is further configured to classify a communication devicelocated on an edge of the cell into the second communication devicegroup and perform the classification according to channel conditions ofthe communication device.
 18. A communication device, comprising:circuitry, configured to transmit channel quality measurementinformation and/or a radio resource management measurement report to acontrol apparatus; receive a pilot transmission configuration from thecontrol apparatus, the pilot transmission configuration comprisinginformation of a pilot sequence allocated to the communication devicebased on the channel quality measurement information and/or a radioresource management measurement report; and transmit a pilot signalbased on the pilot transmission configuration, wherein the communicationdevice is classified into a communication device group among a pluralityof communication device groups based on the channel quality measurementinformation and/or a radio resource management measurement report and isallocated with the pilot sequence belonging to the communication devicegroup, the plurality of communication device groups comprise a firstcommunication device group and a second communication device group,pilot sequences in a first pilot group are allocated to the firstcommunication device group, and pilot sequences in a second pilot groupare allocated to the second communication device group, at least one ofthe following reuse configurations is performed in the case that thepilot sequences are insufficient: at least part of the communicationdevices in the second communication device group reuse at least one ofthe pilot sequences in the second pilot group, and at least onecommunication device in the second communication device group of thecell and at least one communication device in a second communicationdevice group of a neighboring cell which is subjected to the sameclassification reuse at least one of the pilot sequences in the secondpilot group, and at least part of the pilot sequences in the first pilotgroup corresponding to the cell are the same as at least part of thepilot sequences in a first pilot group corresponding to the neighboringcell, and the pilot sequences in the second pilot group corresponding tothe cell are different from the pilot sequences in the second pilotgroup corresponding to the neighboring cell.
 19. The apparatus accordingto claim 1, wherein the circuitry is further configured to configure atleast part of the communication devices in the second communicationdevice group to occupy different time resources so as to transmit atleast one of the reused pilot sequences in the second pilot group, inthe case that the number of the pilot sequences contained in the secondpilot group corresponding to the cell is smaller than the number of thecommunication devices in the second communication device group, and thedifferent time resources correspond to different time slots, and for onetime slot, the communication devices configured to occupy other timeslots do not transmit any data or pilot sequence.
 20. The apparatusaccording to claim 1, wherein the circuitry is further configured todetermine, for each of the part of pilot sequences, a time slot within aframe to be occupied by the communication device in the secondcommunication device group of the cell, so as to coordinate with theneighboring cell.
 21. The apparatus according to claim 4, wherein thepilot sequences in the first pilot group are orthogonal to the pilotsequences in the second pilot group and the reusing is time divisionreusing.
 22. The apparatus according to claim 4, wherein the circuitryis further configured to determine, for each of the part of pilotsequences, a time slot within a frame to be occupied by thecommunication device in the second communication device group of thecell, so as to coordinate with the neighboring cell.
 23. The apparatusaccording to claim 7, wherein the pilot sequences in the first pilotgroup are orthogonal to the pilot sequences in the second pilot groupand the reusing is time division reusing.